Oiltight switchboard pilot light



y 6, 1953 A. B. JOHNSON, JR 2,640,189

OILTIGHT SWITCHBOARD PILOT LIGHT Filed Sept. 20, 1951 A r TOR/V575.

Patented May 26, 1953 OILTIGHT SWITCHBOARD PILOT LIGHT Arthur B.Johnson, Jr., Maywood, Ill., assignor to Furnas Electric Company,Batavia, 111., a corporation of Illinois Application September 20, 1951,Serial No. 247,407

"The present invention relates generally to improvements in switchboardaccessories, and relates more specifically to improvements in theconstruction of oiltight pilot light assemblages especially adapted foruse on control station electric switchboards.

The primary object of my invention is to provide an improved electricpilot light assemblage which is simple and compact in construction andflexible in its adaptations.

It is frequently desirable when assembling a group of electric switchesat a common control station, to include one or more pilot lightsconnected in its several electric circuits so as to clearly indicate thefunctioning thereof. In such stations it is also important that theswitch units and the pilot lights be well protected against entry offoreign matter such as water and oil, and it is furthermore frequentlydesirable to employ different types of electric lamps in the pilot lightunits. In the prior switch board assemblages of this type, it wascustomary to utilize separate and relatively complicated means forsealingly clamping the lamp mounting base to the switch unit support andto likewise clamp the lamp lens to the base or its support; and it wasalso necessary in these prior control stations to provide special lampmounting bases for each different type of lamp bulb which was employedthus further complicating the assemblages and making it difiicult toproperly set up the electric circuits.

It is therefore one important object of my present invention to providean oiltight pilot light unit wherein a single member is utilized tosealingly clamp the lamp mounting base to the main switch support and toalso likewise clamp the lamp lens to the same base.

Another important object of the present invention is to provide anelectric pilot light assembly in which several different types of lightbulbs may be interchangeably associated with a common base structure.

A further object of this invention is to provide an improved oiltightand convertible electric pilot light composed of few sturdy parts toproduce a compact unit adapted to be readily assembled and installedwithin electrical circuits.

Still another object of the invention is to provide an improved electricpilot light assemblage capable of being quickly dismantled for therenewal of burned out light bulbs and for inspection of parts andattachment of terminals.

An additional object of my invention is to provide a pilot light unitespecially adapted to be applied to an oiltight casing for supporting a9 Claims. (Cl. 340-381) group of electric switches at a common controlstation, in a manner similar to the installation of the switch units.

A further object of this invention is to provide an improved electricpilot light unit which may be manufactured and sold at moderate cost fordiverse uses, and which may be easily converted for use with eitherstandard incandescent or neon light'bulbs.

These and other objects and advantages of the invention will be apparentfrom the following detailed description, but the gist of the presentimprovement comprises the provision of an oiltight and convertiblepilotlight unit having a unitary lamp housing base with which different typesof lamp bulbs may be interchangeably associated and caused to cooperatewith a lens which is clamped to the base by the same means which clampsthe base to a support so as to effect oiltight sealing of the entireassemblage.

A clear conception of the improved features constituting the invention,and of the construction and mode of utilizing a typical convertible lampunit embodying the same, may be had by referring to the drawingaccompanying and forming a part of this specification wherein likereference characters designate the same or similar parts in the variousviews.

Fig. l is a side elevation of one of the improved pilot light unitsassembled for the reception ofa standard neon light bulb;

Fig. 2 is a bottom view of the frame and contact assembly of Fig. 1, butwith the lower retainer plate omitted;

Fig. 3 is a section through the pilot light assemblage of Fig. 1, takenalong the line 3-3;

Fig. 4 is a top view of the improved convertible pilot light unit,embodying either a neon or an incandescent lamp;

Fig. 5 is a side elevation of the same pilot light unit but assembledfor the reception of a standard incandescent light bulb;

Fig. 6 is a bottom view of the frame and contact assembly of Fig. 5,with the lower retainer plate removed;

Fig. '7 is a section through the pilot light assemblage of Fig. 5, takenalongthe line 1-1;

Fig. 8 is a bottom view of the lower retainer plate of the unit;

Fig. 9 is a side elevation of one of the improved lenses removed fromthe pilot light unit; and

Fig. 10 is'a side view of the frame of the unit. While the invention hasbeen shown and described herein as having been embodied in a convertiblepilot light unit adapted to interchangeper portion ably cooperate withonly two difierent types of lamps and disposed in upright position, itis not my desire or intention to unnecessarily restrict the utility ofthe improved features or the disposition of the unit by virtue of thislimited embodiment; and it is also contemplated that descriptive termsemployed herein be given the broadest possible interpretation consistentwith the disclosure.

Referring to the drawing, the improved pilot light unit shown therein,comprises in general a unitary frame or base l4 having a tubular upl5provided with external screw threads l5 and also having an integralflange i? at the lower end of the portion iii; a reversible lampretainer 18 detachably secured to the base flange and being cooperablewith a lamp bulb 19 to maintain the same centrally within the tubularbase portion IS; a dome shaped transparent lens 26 coacting with theupper extremity of the tubular portion through a sealing ring 2!, andhaving thereon external screw threads 22 coextensive with the basethreads 16; a support 23 embracing the base portion l5 and coacting withthe base flange ll through. a sealing gasket 24; a single clampingmember or ring nut 25 co operable with the screw threads Iii, 22 toclamp the lens 20 against the base l4 and the latter against the support23 through the ring 2| and.

gasket 24 respectively; a lower mounting plate 26 suspended from thebase flange I! by spacers 21; and terminals 28, 29 cooperable withcontacts for electrically connecting the lamp bulb 19 into a circuit.

The frame or base l4 may be formed of a single piece of durableinsulation and the tubular portion 15 should be carefully bored so as toclear the lamp bulb 19 as well as substitute bulbs of larger diameter.The bulb IQ of Figs. 1 to 3 is of the standard neon 110-220 volt typeand has a metallic threaded supporting or plug end 3! adapted to bescrewed into the sheet metal retainer l8 when positioned as shown inFig. 3 so as to hold the lamp IS in proper position; and the retainer i8is detachably secured to the base flange IT by means of two screws 32.The retainer I8 is electrically connected to the terminal screw 29 by acontact plate 33 and to a voltage dropping resistor 34 as illustrated inFig. 2; and the light bulb H! has an extreme end contact 35 which isinsulated from the metallic screw threaded end 3i thereof and isconnectible with the other terminal screw 28 by a second contact plate36. both plates 33, 38 being attached to the base (4 by screws 31.

When a standard 110 volt incandescent lamp bulb 39 is to beinterchangeably applied to the pilot light as in Figs. 5 to 7 inclusive,the retainer l8 must be reversed as indicated in Fig. '7 in order toaccommodate the larger incandescent bulb 39. A resistor 40 must also beprovided for voltages greater than 110 volt, and this resistor may beinserted between the retainer 18 and plate 33 and is fastened to thebase flange ll by a screw 4| coacting with an opening 42 as shown inFigs. 2 and 6. In this alternative assemblage, the contact plate 36which engages the lamp contact 35, is connected to the terminal screw29; but the retainer I8, contact plates 33, 36, and terminal andattaching screws 28, 29, 31 are all of similar construction so that onlya few parts must be provided when making the conversion.

The dome shaped lens 20 may be formed. of any suitable transparentmaterialsuch as glass or plastic, and besides being provided with thescrew threads 22, this lens has a lower portion 44 of reduced diameteradapted to snugly engage a counterbore in the tubular base portion (5and which is surrounded by the sealing ring 2|. The ring 2| may beformed of rubber or rubber composition, and the sealing gasket 24 whichis interposed between the base flange l1 and the support 23 is alsoformed of similar material and embraces the tubular base portion 15. Apin 45 may be provided between the base flange I! and a hole in thesupport 23 in order to properly posihton the pilot light assemblage andthe gasket 24, and an indicating plate 46 may also be applied to thesupport 23 around the base portion 15. The ring nut 25 has peripheralserrations or lugs as shown in Fig. 4 for facilitating manipulationthereof, and this single nut 25 besides clamping the lens 20 to the baseI4 and the latter to the support 23, compresses the sealing ring ,2! andgasket 24 and also holds the plate 46 in place.

The lower mounting plate 26 which is suspended from the base flange llby means of the spacers 2'1, is secured to these spacers by screws 41'and has one or more peripherally recessed projections d9 riveted orotherwise attached thereto. These projections 49 serve to hold the pilotlight unit in position within a casing preparatory to final applicationof the support 23 which serves as the cover of the casing, and beforethe ring nut 25 has been applied to the screw threads It to finallyclamp the pilot light assemblage to the support. The lens 29, base 14,clamping nut 25, spacers 21, and mounting plate 23 may be utilizedwithout alteration for cooperation with either type of pilot lamp I 9,39, and the electrical connections may be applied to the terminal screws28, 29 while the pilot light unit is being held solely by the lowerplate projections 49.

When the various parts of the improved unit have been properlyconstructed and assembled as above described, so as to accommodateeither a neon or an incandescent lamp bulb, the lower plate 26 will berigidly suspended from the base [4 and the lamp bulb may be firmlypositioned within the retainer l8 before the lens 20 is attached to thebase 14. After the lamp has been inserted, the sealing ring 2! should beapplied about the lens projections 44 and the clamping nut 25' should bescrewed upon the lens threads 22 to firmly unite the lens and ring nut.The lower plate 26 may then be properly positioned within a receivingreceptacle or casing and temporarily held with the aid of the plateprojections 49 and the electrical conductors should be attached to theterminal screws 28, 29, whereupon the cover support 23' and theindicating plate is may be slipped over thetubular base portion [5 andcaused to coact with the gasket 24 and pin 45. The ring nut 25 may thenbe finally applied to the threads I6 of the projection It to firmlyclamp the unit against the support 23 and to compress the ring 2| andgasket 24 into oiltight sealing engagement with the adj acent' parts.

From the foregoing detailed description, it will be apparent that thepresent invention provides a pilot light unit which is simple andcompact in construction and which may be readily converted forinterchangeable use with several types of lamps either by themanufacturer or by the user. The single ring nut 25 serves the dualpurpose of providing an effective oiltight seal both between the base i4 and the lens 20 and between the cover support 23 and the base i 4;.and only a few simple and inexpensive parts are required in order toefiect conversion of the unit for use with either type of lamp bulb i9,39. The various parts of -the improved unit are conveniently accessiblefor inspection, installation, and renewal of lamp bulbs, but arethoroughly protected during normal use, and these pilot lightassemblages may be utilized either singly or in conjunction with varioustypes of switches associated with a common support at control stationsadapted for diverse purposes.

It should be understood that it is not desired to limit this inventionto the exact details of construction or to the precise usage of thepilot light units herein shown and described, for various modificationswithin the scope of the appended claims may occur to persons skilled inthe art.

I claim:

1. In an oiltight pilot light, a lamp housing base formed of insulationand, a support for said base, a lens cooperable with an electric lampconfined within said separate sealing gaskets interposed between saidbase and said support and lens, and a common member for sealablyclamping one of said gaskets between said base and said support andanother between said lens and said base.

2. In an oiltight pilot light, a lamp housing base formed of insulationand having external screw threads, a support for said base, a lenscooperable with an electric lamp confined within said base and alsohaving external screw threads, flexible sealing elements interposedbetween said base and said support and lens, and a common internallythreaded member coacting with said elements and said external base andlens threads to sealingly clamp the base to said support and the lens tothe base.

3. In an oiltight pilot light, a lamp housing base formed of insulation,a support for said base, a lens cooperable with Various types ofelectric lamps confined within said base, a reversible lamp retainer forinterchangeably supporting various types of lamps within said base andsaid lens, and a common member for sealably clamping said base to saidsupport and said lens to said base.

4. In an oiltight pilot light, a lamp housing base formed of insulationand having external screw threads, a support for said base, a lenscooperable with neon or incandescant electric lamps confined within saidbase and also having external screw threads, a reversible lamp retainerfor interchangeably supporting either of said types of lamps within saidbase and said lens, flexible sealing elements interposed between saidbase and said support and lens, and a common internally threaded membercoacting with said elements and said external base and lens threads tosealingly clamp the base to said support and the lens to the base.

5. In an oiltight pilot light, a lamp housing base formed of insulationand having an integral flange and a centrally bored tubular portion provided with external screw threads extending away from said flange, asupport for said base having said flange on one side thereof and saidscrew threads projecting beyond its opposite side, a lens cooperablewith an electric lamp confined within said base and also having externalscrew threads coextensive with said base threads, flexible sealingelements interposed between said lens and base and support, and a ringnut coacting with said base and lens threads to simultaneously clampsaid elements in place.

6. In an oiltight pilot light, a lamp housing base formed of insulation,a support for said base, a lens cooperable with an electric lampconfined Within said base, sealing elements between said base and saidsupport and lens, a common member for sealably clamping said elementsand said base to said support and said lens to said base, and means forholding said base in a predetermined position prior to application ofsaid clamping member.

7. In an oiltight pilot light, a base formed of insulation and having anexternally threaded tubular portion and an integral external flange atone end thereof, a lamp bulb retainer secured to said flange, a lenscoacting with the opposite end of said tubular portion, a supportembracing said tubular portion adjacent to said flange, flexible sealingelements interposed. between said flange and support and between saidlens and said tubular portion, and a single ring nut coacting with thethreads of said tubular portion to clamp said elements between theadjacent parts.

8. In an oiltight pilot light, a base formed of insulation and having anexternally threaded tubular portion and an integral external flange atone end thereof, a lamp bulb retainer secured to said flange, a lenscoacting with the opposite end of said tubular portion, a supportembracing said tubular portion adjacent to said flange, means suspendedfrom said flange for holding said base in a predetermined positionbefore said support is applied thereto, and a single ring nut cooperablewith the threads of said tubular portion to clamp said lens to said baseand said base to said support.

9. In an oiltight pilot light, a base formed of insulation and having anexternally threaded tubular portion and an integral external flange atone end thereof, a lamp bulb retainer secured to said flange, a lenscoacting with the opposite end of said tubular portion, a supportembracing said tubular portion adjacent to said flange, means cooperablewith the threads of said tubular portion to clamp said lens to said baseand said base to said support, and means cooperable with said flange andsaid retainer for interchangeably accommodating electric lamp bulbs ofdifierent types.

ARTHUR B. JOHNSON, JR.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,664,288 Sparkes Mar. 27, 1928 1,858,994 Kirkland May 1'7,1932 2,092,371 Douglas Sept. 7, 1935 2,560,099 Frank July 10, 1951

